HURRICANES IRMA AND MARIA

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1 EXECUTIVE SUMMARY HURRICANES IRMA AND MARIA Bloomberg Philanthropies USVI Hurricane Recovery and Resilience Task Force 1

2 Hurricanes Irma and Maria, both Category 5 storms with wind gusts of up to 178 MPH at their centers, impacted the USVI within two weeks of each other on September 6 and September 20, Hurricane Irma most affected the St. Thomas-St. John district and damaged St. Croix as well; Hurricane Maria most affected St. Croix, which by then had become the staging ground for recovery operations for areas damaged by Irma, and further damaged what was already damaged on St. Thomas and St. John. The hurricanes caused five direct deaths in the Territory. HURRICANE IRMA Hurricane Irma approached the US Virgin Islands as a Category 5 hurricane with sustained winds of 178 MPH at its center. On September 6, the storm s center passed just north of St. Thomas around 2 p.m. AST, leading to sustained winds of 106 MPH and gusts of up to 137 MPH as measured by surface observation stations. Irma moved northwest and passed roughly 50 miles north of Puerto Rico around 8 p.m. AST on September 6. The final path of the hurricane was west of the National Hurricane Center s (NHC) predictions, which had also predicted the storm would turn northward earlier than it did. 1 The wind at the hurricane s center attained near maximum strength as the hurricane approached St. Thomas (see chart: Wind speed at Hurricane Irma center vs. distance to downtown Charlotte Amalie, St. Thomas). SAFFIR- SIMPSON SCALE: CATEGORY 5 DEFINITION Catastrophic damage will occur: A high percentage of framed homes will be destroyed, with total roof failure and wall collapse. Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months. The NHC began providing Impact-Based Decision Support Services (IDSS) for Hurricane Irma starting on September 1; IDSS included briefings coordinated through the FEMA Hurricane Liaison Team and included the USVI and Puerto Rico as well as several states. The NHC issued the first Hurricane Watch for Irma to the USVI at 3 p.m. AST on September 4; this changed to a Hurricane Warning issued on September 5 at 3 p.m. AST. The Hurricane Warning was discontinued on September 7 at 3 a.m. AST (see table: Timeline of Hurricanes Irma and Maria). Irma produced significant storm surge in the St. Thomas-St. John District. While the National Ocean Service (NOS) tide gauge on St. Thomas (Charlotte Amalie) went offline during the hurricane and could not transmit a peak storm surge level, NHC estimated a surge of at least 2.3 ft. and possibly greater. Hurricane Irma caused extensive damage Wind speeds: 157 MPH or higher National Hurricane Center Hurricane Irma, pre-and post-event night lights variation NASA 1 John P. Cangialosi, Andrew S. Latto, and Robbie Berg. Tropical Cyclone Report: Hurricane Irma. Report no. AL National Hurricane Center, National Oceanic and Atmospheric Association National Weather Service. May 30, Accessed June 15, USVI Hurricane Recovery and Resilience Task Force 23

3 Hurricanes Irma and Maria Hurricane Irma Category 5 5 Hurricane Maria Landfall date September 6 September 20 Landfall location St. Thomas / St. John St. Croix Worst-affected areas St. Thomas / St. John St. Croix Maximum measured sustained wind speeds Maximum measured wind gusts in the USVI 106 MPH* 107 MPH* 137 MPH* 137 MPH* Rainfall Data not available* 5 in.+* Storm surge ft.+* ft.+* Storm tide ft.+* ft.+* Direct deaths 3 2 * Precipitation and tide measuring instruments were knocked offline or destroyed STORM SURGE, STORM TIDE, AND INUNDATION Wind speed at Hurricane Irma center vs. distance to downtown Charlotte Amalie, St. Thomas MPH, vertical axis; miles, horizontal axis Task Force analysis based on NHC data ,000-2,500-2,000-1,500-1, ,000 1,500 2,000 2,500 According to the NHC, storm surge is defined as the abnormal rise of water generated by a storm, over and above the predicted astronomical tide, and is expressed in terms of height above normal tide levels. Because storm surge represents the deviation from normal water levels, it is not referenced to a vertical datum. Storm tide is defined as the water level due to the combination of storm surge and the astronomical tide, and is expressed in terms of height above a vertical datum, i.e., the North American Vertical Datum of 1988 (NAVD88) or Mean Lower Low Water (MLLW). Inundation is the total water level that occurs on normally dry ground as a result of the storm tide, and is expressed in terms of height above ground level. At the coast, normally dry land is roughly defined as areas higher than the normal high tide line, or Mean Higher High Water (MHHW). USVI Hurricane Recovery and Resilience Task Force 24

4 throughout St. Thomas, St. John, Water Island, and the district s surrounding smaller islands. Across the Territory, high wind speeds stripped foliage, brought down power and telephone lines, sheared off roofs, and turned debris into projectiles. Residents who followed instructions to shelter in place found themselves in a fight for survival as powerful winds sucked furniture out of homes after windows or doors blew out. People reported crawling atop their refrigerator to hide in the space between the fridge and cabinetry, or piling furniture against doors and lying on their back to press against the blockade with their feet. Although the damage to St. Croix was not so extensive as that in the St. Thomas-St. John District, roughly 70 percent of St. Croix s homes and structures still suffered some damage from the storm. Timeline of Hurricanes Irma and Maria September 1 September 4 September 5 September 6 September 7 IDSS for Irma Hurricane Watch issued for Irma Hurricane Warning issued for Irma Seaports closed Airports closed Hurricane Irma landfall in the USVI Hurricane Warning lifted for Irma Hurricane Irma was responsible for three direct deaths in the USVI. 2 Extensive damage to power, Internet and cable lines resulted in an almost Territory-wide communications and power blackout. Residents of St. John, Water Island, and the USVI s other smaller islands were stranded for days while ports were closed, ferries did not run, and sunken vessels made navigation treacherous. The damage to airports on St. Thomas and St. Croix effectively stranded the entire USVI population for weeks following Hurricane Irma in many cases, trapping people who d lost everything in the hurricane and were ready to leave the USVI, only to endure a second hurricane just two weeks later. Private individuals and charters alike began to run boats between the USVI and Puerto Rico to give people a chance to get to the still-open San Juan airport (SJU). September 14 September 17 September 18 September 20 September 20 IDSS for Maria Hurricane Watch issued for Maria Hurricane Warning issued for Maria Hurricane Maria landfall in the USVI Hurricane Warning lifted for Maria August 25 September 10 St. Thomas St. John St. Thomas St. John Impact of Hurricane Irma on leaf cover on St. Thomas and St. John NASA 2 Direct deaths are defined by the National Hurricane Center as occurring as a direct result of the forces of the tropical cyclone... These include those persons who drowned in storm surge, rough seas, rip currents, and freshwater floods. Direct deaths also include casualties resulting from lightning and wind-related events (e.g., collapsing structures). Deaths occurring from such factors as heart attacks, house fires, electrocutions from downed power lines, vehicle accidents on wet roads, etc., are considered indirect deaths. USVI Hurricane Recovery and Resilience Task Force 25

5 Hurricane Irma wind gust footprint Pan American Health Organization/World Health Organization and Applied Research Associates Wind gust speed (MPH), Hurricane Irma Pan American Health Organization/World Health Organization and Applied Research Associates USVI Hurricane Recovery and Resilience Task Force 26

6 HURRICANE MARIA Just 14 days after Hurricane Irma hit St. Thomas and St. John, Hurricane Maria bore down on St. Croix. Starting on September 11, it took only five days for a tropical wave to form into Hurricane Maria on September 16, and by September 18, Maria was a Category 5 storm. The hurricane made landfall on St. Croix early in the morning on September 20 with peak wind speeds at its center of 172 MPH as it passed roughly 25 nautical miles south of the island. Peak sustained winds of 107 MPH with gusts of 137 MPH were reported on St. Croix near the northeast edge of Maria s eyewall. Maria continued west-northwestward toward Puerto Rico, where it made landfall late in the morning of September 20, causing catastrophic damage. The hurricane attained nearly maximum strength when it was nearest to St. Croix (see chart: Wind speed at Hurricane Maria center vs. distance to downtown Christiansted). The NHC began providing Impact-Based Decision Support Services (IDSS) starting on September 14; IDSS included briefings coordinated through the FEMA Hurricane Liaison Team and included the USVI and Puerto Rico. The NHC issued the first Hurricane Watch for Maria to the USVI at 9 p.m. AST on September 17; this upgraded to a Hurricane Warning issued on September 18 at 3 p.m. AST. The Hurricane Warning was discontinued on September 20 at 9 p.m. AST. Although the tide gauge at Limetree Bay on St. Croix measured a peak water level of 2.8 ft. relative to Mean Higher High Water (MHHW), the sensor went offline during the storm and likely did not record the actual highest water level. NOAA surge simulations suggest maximum inundation levels of 1-3 ft. above ground level on St. Thomas and St. John. Hurricane Maria affected all of the USVI, but St. Croix most severely, causing significant wind damage to roofs, structures, foliage, and aerial power and phone lines. The deluge of rain from Wind speed at Hurricane Maria center vs. distance to downtown Christiansted MPH, vertical axis; miles, horizontal axis ,500-1, ,000 1,500 2,000 2,500 3,000 3,500 4,000 Task Force analysis based on NHC data Hurricane Maria, pre-and post-event night lights variation NASA USVI Hurricane Recovery and Resilience Task Force 27

7 Maria resulted in widespread flooding and mudslides throughout the Territory. St. Croix experienced at least an estimated 5-7 inches of rainfall; throughout the USVI and especially in the St. Thomas-St. John district the rain further damaged structures already damaged in Hurricane Irma (see graphic: Hurricane Maria rainfall patterns). In the USVI, the hurricane was responsible for the direct deaths of two people. Hurricane Maria wind gust footprint Pan American Health Organization/World Health Organization and Applied Research Associates Hurricane Maria rainfall patterns NASA USVI Hurricane Recovery and Resilience Task Force 28

8 Selected surface observations for Hurricanes Irma and Maria NHC reports for Hurricanes Irma and Maria St. Thomas Instrument and identifier Rupert Rock (XRUP) Cyril E. King Airport (TIST) Buck Island (XBUK) Coordinates 18.33N 64.93W 18.33N 64.97W 18.28N 64.90W Minimum sea level pressure Date/time (UTC) Pressure (mb) Maximum surface wind speed Date/time (UTC) Sustained (MPH) Gust (MPH) 05/ / ^ 87^ 06/ / Flooding and precipitation Storm surge (ft) Storm tide (ft) Estimated inundation (ft) Total rain (in) NOS site at Charlotte Amalie, St. Thomas (CHAV3) 18.34N 64.92W 06/ / ** 1.71 ** 1.3 ** Irma St. John Savana Island (XSAV) NOS site at Lameshur Bay, St. John (LAMV3) 18.34N 65.08W 18.32N 64.72W 06/ / NOS site at Christiansted Harbor, St. Croix (CHSV3) 17.75N 64.70W 06/ / Henry E. Rohlsen Airport (TISX) 17.68N 64.90W 06/ / St. Croix NOS site at Limetree Bay, St. Croix (LTBV3) 17.70N 64.75W 06/ / Sandy Point National Wildlife Refuge, St. Croix (XCRX) 17.68N 64.90W 06/ St. Thomas Rupert Rock, St. Thomas (XRUP) 18.33N 64.93W 20/ / * 64 Maria St. John NOS site at Lameshur Bay, St. John (LAMV3) CarlCOOS buoy south of St. John (41052) NOS site at Christiansted Harbor, St. Croix (CHSV3) 18.32N 64.72W 18.25N 64.76W 17.75N 64.70W 20/ / / / / NOS site at Lime Tree Bay, St. Croix (LTBV3) 17.70N 64.75W 20/ / * * 3.17* 2.80* St. Croix Christiansted, St. Croix (CVAV3) 17.74N 64.62W 20/ Sandy Point National Wildlife Refuge, St. Croix (XCRX) 17.68N 64.90W 20/ / * Incomplete data ^ Site damaged during storm ** Station went offline and did not transmit a peak water level during the event. Peak values represent the highest transmitted prior to outage. USVI Hurricane Recovery and Resilience Task Force 29